1. Field of Invention
This invention relates to water faucets used for baths and showers.
2. Prior Art
Several types of faucets for bathing are available. Some have separate valves and handles for hot and cold. Others have a single control lever which rotates on two axes, controlling flow and mixture. Some have a single control lever which rotates on only one axis for temperature control, providing full flow volume at all positions besides "off". Shower heads are available which provide an auxiliary flow control valve allowing temporary water shutoff for economy during a shower. Each of these has disadvantages which are solved by the present invention.
The common dual faucet assembly requires an iterative temperature adjustment at the start of each shower while the hot water temperature stabilizes after reaching the valve. The adjustment period increases with the distance to the water heater. The water pipe absorbs more heat at first, so the hot water temperature gradually rises to a stabilization point. After stabilization, changing the hot water flow rate has an immediate effect on shower temperature. However, the new hot flow rate changes the percentage of heat lost in transit from the heater, so the output temperature will gradually change to a new stabilization point, prompting further adjustment. The cold water flow rate adds another variable. The variables of hot and cold flow rate, hot temperature, stabilization rate, mixed temperature, and total flow rate, are interdependent.
Time and water is wasted during the adjustment period. The total waste is substantial, since this activity is performed every day by many people. As a ballpark figure, assume 100,000,000 baths or showers a day are taken in the U.S., with the following three roughly estimated categories of waste. This invention offers partial savings in the second and third categories, although its main claimed benefit is user convenience.
______________________________________ WASTED WASTED SECONDS GALLONS DESCRIPTION ______________________________________ (a) 20 1 Water in transit from heater to valve (b) 20 1 Iterative temperature and flow adjustment (c) 0 1 Water running while soaping only TOTAL DAILY WASTE IN U.S. 1,000,000 man-hours 300,000,000 gallons TOTAL YEARLY WASTE 365,000,000 man-hours IN U.S. 100,000,000,000 gallons ______________________________________
A shower faucet often found in hotels has a single control handle for the hot/cold mixing ratio, which also turns the flow on or off. Adjustment is simplified by the lack of graduated flow control. The tradeoff is waste due to excessive flow. Iterative temperature adjustment is still required, although it is made easier.
An auxiliary flow valve can be installed past the water mixing point, providing independent control of the total flow rate. Such a valve is available in some shower heads, for temporary shutoff, saving in category c). However, the water is cooler when restarted, due to heat loss while the flow is stopped. Shower heads are generally not adequately leakproof to provide a primary shutoff, so the mixture valves are used, and must be readjusted at each shower.
Such an auxiliary valve can be fully leakproof, and the mixture controls left at their last setting between showers. However, cold water then runs during startup, wasting both water and time.
Another approach is to heat water at its point of use. This is effective and efficient in terms of time, water, and heating energy. However, it is expensive to install a water heater at each point of use, and it requires the skills of both an electrician and plummer. It also adds complexity and priority to maintenance and repair. Improper or damaged installation presents electric shock hazard at its most dangerous site.